Method of and device for extracting cartridge cases

ABSTRACT

Apparatus for extracting a cartridge formed of an elastic material from the chamber of a firearm. The apparatus includes a breech block and an obturating member in the form of a circular disc which is secured to the end of the breach block facing the chamber. The obturating member defines a recess at its periphery which receives a part of the cartridge case as the case is deformed in response to the pressure heat generated at the time of firing. As a result, movement of the breech block with the obturating member secured thereto subsequent to firing results in the removal of the cartridge case. The case may subsequently be removed from the obturating member by lateral movement of the case relative to such member.

United States Patent Aldrin METHOD OF AND DEVICE FOR EXTRACTING CARTRIDGE CASES [75] Inventor: Henry Wilhelm Aldrin, Degerfors,

Sweden [73] Assignee: AB Bofors, Bofors, Sweden [22] Filed: Dec. 26, 1973 [21] Appl. N0.: 427,597

[30] Foreign Application Priority Data Jan. 8, 1973 Sweden..'.....'. 7300177 [52] US. Cl 42/25; 89/26 [51] Int. Cl. F41c 15/00 [58] Field of Search 42/25; 89/26 [56] References Cited UNITED STATES PATENTS 2,473,555 6/1949 Weiss 89/26 3,008,258 11/1961 Johnson 89/26 3,1 14,290 12/1963 Harvey et al. 89/26 3,144,727 8/1964 De Caro et al. 42/25 3,609,904 10/1971 Scanlon 42/25 FOREIGN PATENTS OR APPLICATIONS 588,998 12/1933 Germany 42/25 Primary ExaminerBenjamin A. Borchelt Assistant Examiner-C. T. Jordan Attorney, Agent, or FirmPollack, Philpitt & Vande Sande [57] ABSTRACT Apparatus for extracting a cartridge formed of an elastic material from the chamber of a firearm. The apparatus includes a breech block and an obturating memher in the form of a circular disc which is secured to the end of the breach block facing the chamber. The obturating member defines a recess at its periphery which receives a part of the cartridge case as the case is deformed in response to the pressure heat generated at the time of firing. As a result, movement of the breech block with the obturating member secured thereto subsequent to firing results in the removal of the cartridge case. The case may subsequently be removed from the obturating member by lateral movement of the case relative to such member.

3 Claims, 11 Drawing Figures PATENTEDJUN 24 1915 SHEET FIG.

PATENTEDJUN24 I975 3.890.731

1 METHOD OF AND DEVICE FOR EXTRACTING CARTRIDGE CASES The present invention relates to a method of, and a device for, extracting cartridge cases from the chamber of a firearm after firing. The invention is particularly intended to beapplied when cartridge cases made of plastic material are used.

It is previously kno w n to use cartridge cases made of plastic provided with bottomplates made of metal, particularly brass. However, the use of such a metal bottom plate involves a considerable cost in the manufacture, and it is therefore desirable to eliminate the bottom plate and use cartridge cases made entirely of plastic. The problem when using such cartridge cases, however, is that it has proved to be difficult to achieve effective extraction of the cartridge case after the firing.

The present invention gives a solution of the abovementioned problem of extracting cartridge cases made entirely of plastic. The characteristic properties of the invention will be noted from the claims.

The device according to the invention will be described in more detail with reference to the attached drawings, in which FIG. 1 shows a cross-section of a part of a barrel with a conventional device for the extraction of metal cartridge cases or plastic cartridge cases with metal bottoms;

FIG. 2 shows a corresponding cross-section of a barrel provided with a first embodiment of the device according to the invention;

FIGS. 3 and 4 show sections on a larger scale of a part of the device shown in FIG. 2;

FIGS. 5 and 6 show the releasing of the cartridge case from the breech block after the extraction; and

FIGS. 7-11 show another embodiment of the device according to the invention.

FIG. 1, which illustrates the present position of the technology, shows a barrel 1 with a breech block 2, which is provided with conventional extractor hooks 3, which in a known way engage the rear flange 4 ofa cartridge case 5 made of metal. The breech block is provided with thread sectors 6, for securing the breech block in the ramming position shown. The locking is thus accomplished by means of a so-called screw mechanism.

In the device shown in FIGS. 2-6, the breech block 12 is provided with a cupped obturating sleeve 13, which is rotatably fastened to the breech block by means of a locking device 14 (FIG. 5). The obturating sleeve 13 encloses the rear part of a cartridge case 15, which is made entirely of plastic and is provided with a detonator 17. The obturating sleeve constitutes a rear support for the cartridge case, and also functions as an obturation member between the breech block 12 and the barrel 1], and also as an extractor for the cartridge case. On the inside of the cylindrical part of the obturating sleeve 13, there is a peripheral groove 18, as is clearly shown in FIGS. 3 and 4.

FIG. 3 shows the cartridge case 15 in the rammed position before firing. When the round is fired, the cartridge case 15, under the influence of the very high pressure generated in it will be pressed against the barre] 11 and the obturating sleeve 13, as indicated by the arrows in FIG. 4. The cartridge case 15 will then be deformed, so that the groove 18 will be filled up with material from the cartridge case, whereby such a connection between the obturating sleeve 13 and the cartridge case 15 is obtained that it will be possible to extract the cartridge case. At the time of firing, the obturating sleeve 13, in turn, is pressed against the inside of the barrel, whereby efficient obturation against the barrel is obtained.

After the firing, the breech block I2 is turned to its open position. Because of the rotatable fastening device I4, the obturating sleeve 13 will remain in its position, and will thus not prevent the breech block from being turned. When the breech block is retracted, the cartridge case 15 is extracted from the chamber together with the obturating sleeve 13.

FIGS. 5 and 6 show the releasing of the cartridge case from the obturating sleeve after the extraction. For this purpose, the breech block 12 is provided with ejector rods 19, 20, between which there is a ring 21. The rods 19 are arranged in axial holes in the breech block, and the rods 20 go through holes, also axially arranged, in the obturating sleeve 13, and through a ring-shaped recess 22 (FIG. 2) in the breech block, in which recess also the ring 21 is arranged.

When the cartridge case 15, with the aid of the breech block, has been extracted from the chamber, the rods 19 come into contact with the face 23 of stationary member 24. During the continued movement rcarwards, the rods 19, via the ring 21, will actuate the rods 20, which, in turn, eject the cartridge case from the obturating sleeve 13.

It should be obvious that the groove 18 in the obturating sleeve must be given such a size and form that the extraction of the cartridge case from the chamber is ensured, but also, however, so that the welt on the cartridge case which engages in the groove will not be sheared off when the cartridge case is ejected from the obturating sleeve. It should also be obvious that the groove 18 can be made in many ways other than those shown in the drawing, and can also be replaced by e.g. rifling, profiles, knurling or the like.

In the embodiment shown in FIGS. 7-1I, the obturating sleeve has been replaced by a circular obturating disc 33, which in the same way is rotatably attached to the breech block 32. At its periphery, the disc 33 is provided with a semi-circular recess 38, the bottom part of t which is made with a larger radius than the opening facing the cartridge case 35. At the firing, plastic material from the cartridge case 35 is pressed into the recess 38, as shown in FIGS. 8 and 9, whereby a connection with the disc 33 is achieved. The cartridge case is thereafter extracted from the chamber in the same way as described above (FIG. 10). With this embodiment, however, no ejection device is required for releasing the cartridge case from the obturating disc 33 after the extraction. Since the recess 38 is located at the periphery of the disc 33, the cartridge case can be pushed away sideways from the disc 33, as shown in FIG. 11, e.g. by the following cartridge that is to be rammed into the chamber.

I claim:

1. Apparatus for extracting a cartridge case formed of an elastic material from the chamber of a firearm comprising:

a breech block,

an obturating member in the form of a circular disc secured to the end of said breech block facing the chamber,

said obturating member defining a recess at its periphery for receiving a part of the cartridge case as said member.

3. The cartridge case extracting apparatus of claim 2 wherein said recess comprises an aperture which, as measured in a plane normal to the axis of said case, is of greater cross-sectional area with increasing distance from the face of said disc-shaped member which faces said chamber, whereby said case becomes securely attached to said member at the time of firing but may readily be detached by said lateral movement. 

1. Apparatus for extracting a cartridge case formed of an elastic material from the chamber of a firearm comprising: a breech block, an obturating member in the form of a circular disc secured to the end of said breech block facing the chamber, said obturating member defining a recess at its periphery for receiving a part of the cartridge case as it is deformed in response to thE pressure and heat generated at the time of firing, whereby movement of said breech block with said obturating member secured thereto subsequent to firing results in removal of said cartridge case.
 2. The cartridge case extracting apparatus of claim 1 wherein said recess in said disc-shaped obturating member is open at the periphery of said member to permit the separation of the case from said member by the exertion of lateral movement of said case relative to said member.
 3. The cartridge case extracting apparatus of claim 2 wherein said recess comprises an aperture which, as measured in a plane normal to the axis of said case, is of greater cross-sectional area with increasing distance from the face of said disc-shaped member which faces said chamber, whereby said case becomes securely attached to said member at the time of firing but may readily be detached by said lateral movement. 